A New and Inexpensive Pyranometer for the Visible Spectral Range

Martinez, Maria Elisa Marciano; Andújar, José Manuel; Enrique, Juan M.

doi:10.3390/s90604615

Cited by 51 publications

(39 citation statements)

References 23 publications

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“…The negative bias (Figure 4) indicated that the portable system values were higher on average than those at AmeriFlux sites. Possible explanations for this bias are sensor degradation [ Feuermann and Zemel , 1993; Martínez et al , 2009], sensor out‐of‐calibration, or dirty sensor.…”

Section: Resultsmentioning

confidence: 99%

Empirical assessment of uncertainties of meteorological parameters and turbulent fluxes in the AmeriFlux network

Schmidt

Hanson

et al. 2012

J. Geophys. Res.

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[1] Terrestrial ecosystem-atmosphere exchange of carbon, water vapor, and energy has been measured for over a decade at many sites globally. To minimize measurement and analysis errors, quality assurance data have been collected over short periods along-side tower instruments at AmeriFlux research sites. Theoretical and empirical error and uncertainty values have been reported for various aspects of the eddy covariance technique but until recently it has not been possible to constrain network level variation based on direct comparison of side-by-side measurements. Paired observations, although rare in practice, offer a possibility to obtain real-world error estimates for flux observations and corresponding uncertainties. In this study, we report the relative instrumental errors from the AmeriFlux quality assurance and quality control (QA/QC) site intercomparisons of 84 site visits (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012). Relative errors, including random and systematic instrumental errors, are presented for meteorological and radiation variables, gas concentrations, and the turbulent fluxes. The lowest relative errors (<2%) were found for the meteorological parameters, while the largest relative errors were found for latent heat and CO 2 fluxes. The mean relative instrumental error for CO 2 flux averaged À8.2% (underestimation by the tower instruments). Sensible and latent heat fluxes exhibited mean errors of À1.7% and À5.2%, respectively. Deviation around the mean was also largest for the turbulent fluxes, approaching 20%. Because the data collected during QA/QC site visits are used to identify and correct errors, our results represent a conservative estimate of instrumental errors in the AmeriFlux database. Overall, the presented results confirm the high quality of the network data and underline its status as a valuable data source for the research community.

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Section: Resultsmentioning

confidence: 99%

Empirical assessment of uncertainties of meteorological parameters and turbulent fluxes in the AmeriFlux network

Schmidt

Hanson

et al. 2012

J. Geophys. Res.

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“…This logic is the basis for the development of an open source colorimeter [17], an open source control system for a solar plant [18], and a new and inexpensive pyranometer [19]. These are only some example of research instruments developed following the DIY approach that have been shared, in line with the maker movement philosophy.…”

Section: Introductionmentioning

confidence: 99%

A Low-Cost Environmental Monitoring System: How to Prevent Systematic Errors in the Design Phase through the Combined Use of Additive Manufacturing and Thermographic Techniques

Salamone

Danza

Meroni

et al. 2017

Sensors

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nEMoS (nano Environmental Monitoring System) is a 3D-printed device built following the Do-It-Yourself (DIY) approach. It can be connected to the web and it can be used to assess indoor environmental quality (IEQ). It is built using some low-cost sensors connected to an Arduino microcontroller board. The device is assembled in a small-sized case and both thermohygrometric sensors used to measure the air temperature and relative humidity, and the globe thermometer used to measure the radiant temperature, can be subject to thermal effects due to overheating of some nearby components. A thermographic analysis was made to rule out this possibility. The paper shows how the pervasive technique of additive manufacturing can be combined with the more traditional thermographic techniques to redesign the case and to verify the accuracy of the optimized system in order to prevent instrumental systematic errors in terms of the difference between experimental and actual values of the above-mentioned environmental parameters.

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“…We used polytetrafluoroethylene (TeflonTM) as a cosine corrector, to minimize the effects of incidence angle on observation accuracy. Its optical properties remain constant over a wide range of wavelengths, from UV up to near-infrared, and it is widely used for radiation sensor cosine correction [28][29][30]. Light transmitted through the diffuser radiates, according to Lambert's cosine law.…”

Section: Dome and Cosine Correctormentioning

confidence: 99%

“…The silicon photoelectric detector is temperature-dependent [41]: the output increases as the device's temperature goes up. The general means of accurate observation is temperature control [30]. In our design, the upward and downward radiation is divided, to yield a spectral albedo for each band.…”

Section: Errors Induced By the Spectral Albedometer Designmentioning

confidence: 99%

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Design of a Novel Spectral Albedometer for Validating the MODerate Resolution Imaging Spectroradiometer Spectral Albedo Product

2018

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Land surface shortwave broadband albedo is a key parameter in general circulation models and surface energy budget models. Multispectral satellite data are typically used to generate broadband albedo products in a three-step process: atmospheric correction, for converting the top-of-atmosphere observations to surface directional reflectance; angular modeling, for converting the surface directional reflectance to spectral albedo of each individual band; and finally, narrowband-to-broadband conversion, for transforming the spectral albedos to broadband albedos. Spectroradiometers can be used for validating surface directional reflectance products and pyranometers or broadband albedometers, for validating broadband albedo products, but spectral albedo products are rarely validated using ground measurements. In this study, we designed a new type of albedometer that can measure spectral albedos. It consists of multiple interference filters and a silicon detector, for measuring irradiance from 400-1100 nm. The linearity of the sensors is 99%, and the designed albedometer exhibits consistency up to 0.993, with a widely-used commercial instrument. A field experiment for measuring spectral albedo of grassland using this new albedometer was conducted in Yudaokou, China and the measurements are used for validating the MODerate Resolution Imaging Spectroradiometer (MODIS) spectral albedos. The results show that the biases of the MODIS spectral albedos of the first four bands are −0.0094, 0.0065, 0.0159, and −0.0001, respectively. This new instrument provides an effective technique for validating spectral albedos of any satellite sensor in this spectral range, which is critical for improving satellite broadband albedo products.

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A New and Inexpensive Pyranometer for the Visible Spectral Range

Cited by 51 publications

References 23 publications

Empirical assessment of uncertainties of meteorological parameters and turbulent fluxes in the AmeriFlux network

Empirical assessment of uncertainties of meteorological parameters and turbulent fluxes in the AmeriFlux network

A Low-Cost Environmental Monitoring System: How to Prevent Systematic Errors in the Design Phase through the Combined Use of Additive Manufacturing and Thermographic Techniques

Design of a Novel Spectral Albedometer for Validating the MODerate Resolution Imaging Spectroradiometer Spectral Albedo Product

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